The Middlesbrough manager Gareth Southgate has told clubs rumoured to be planning raids for his players during the January transfer window to put up or shut up.

Chelsea have been linked with a move for the Turkey international Tuncay Sanli, while Tottenham Hotspur continue to be associated with the England winger Stewart Downing and it has been suggested that both will leave the Riverside next month. But Southgate neither wants to, nor has to, sell any of his better players and is adamant that any potential purchaser will have to fight to prise away Middlebrough's key men.

"We are not here for other football clubs to walk over and if people think they can just take our players out, then they are wrong," he said. "We are not here to help other clubs. No one is going to help us.

"We want as much stability as we can and if people do have an interest in our players, they need to get on with it. They need to make their ideas known to us so we can either say, 'Thank you very much, there you go,' or 'No, nothing's going to happen', and they can then move on with their lives."

Southgate has also warned any club preparing an offer not to bide their time in the hope of snaring a bargain late in the window.

That is the situation that transpired in summer 2007 when Everton, who Middlesbrough meet on Boxing Day, ended weeks of speculation by tabling an £11.25m offer for striker Yakubu Ayegbeni. The Nigeria international eventually completed his move to Goodison Park on 30 August, leaving the Teeside club no time to recruit a replacement.

"That's something you want to try to avoid. We are consistent as a club on our stance on that," added Southgate. "The longer time goes on, the less likely you are to want to part with people because you can't get people in to replace them."

Meanwhile, Southgate has defended Julio Arca over the midfielder's reckless tackle on Fulham's Andy Johnson on Saturday for which he was booked but most observers felt deserved a red card.

"When you look at the pictures and you slow them down, they don't look good, so I can understand people's reaction to that," he said. "But I know the nature of our player and Julio isn't a malicious type at all. He wouldn't have wanted to cause any harm, that's for certain."